I work out for 1 hour daily in the morning. My trainer told me to stay warm i.e. keep the muscles warm, throughout the day (or at least most of the time) because it helps muscle gain.

That is, he wanted to say that after doing exercise, instead of wearing half shirts, I have to wear full shirts or jackets to avoid direct contact with cold air so that my muscles will stay warmer, which will support me gaining muscle.

When I asked for clarification about it, he told me that his trainers used to advise him like that. So, is it really useful and does it make any difference, or is this just another myth?

  • A possibly related article: startingstrength.com/index.php/site/article/…
    – user4644
    Dec 10, 2012 at 17:50
  • 2
    One tip - If you ever ask a trainer something and they respond with "That's how I was trained", run away. Fast. That means they have blindly accepted what the person before them did, right or wrong, and have done no personal research or education.
    – JohnP
    Sep 7, 2013 at 15:51
  • Thanks fort he question to be answered... but I accept that it would keep your body and muscles better to help and or encourage growth. In the muscle category that is being worked on, so avoid short sleeves and try to wear pants.
    – bdg
    Jul 20, 2018 at 0:44

3 Answers 3


The answer to this question depends on whether you believe you should allow or prevent inflammation during recovery. This article explains both sides of the issue.

Your trainer probably believes that some level of inflammation, extra blood flow, etc. is beneficial to recovery, and that a jacket can significantly affect that.

Inflammation begins after you do a heavy set of lifts. Your muscles are stressed during the workout, and this triggers inflammation as part of the recovery process. Regardless of how you feel at this stage, your lifting performance will be reduced.

Some people believe that this inflammation is necessary for proper recovery and adaptation. However, that review article argues that the science is not settled. Should you use ibuprofen to help yourself deal with inflammation and get back to the gym a bit sooner? Or does that hurt your strength gains by interfering with the natural recovery process? The author's conclusion is:

if anti-inflammatory interventions delay healing or blunt gains, they don’t do it by very damn much. Conversely, if they aid return to function or actually promote gains, again, it’s not by very damn much.

It seems to me that if the effects of doing something as drastic as using anti-inflammatory drugs or ice are so inconsistent or insignificant to your training, then the effects of wearing or not wearing a jacket will be much less important.

  • thanks for your answer, but its really too complicated information to understand :) Dec 11, 2012 at 11:50
  • 1
    Can you add some information from the article here (feel free to quote relevant parts and use the link as a reference) to prevent link rot?
    – Matt Chan
    Dec 11, 2012 at 13:28

There are varying ranges of educational levels for trainers. They could be non-high school graduates that sat for one of the 4-6 hour personal training courses to those having a Bachelor's in Exercise Science with a Master's of Exercise Physiology. Some of the time trainers will not know the reasoning behind a method (keeping the muscles warm in this case); and rather that it is a widely accepted norm.

That being said, keeping muscles warm post heavy lifting is a viable technique for most lifters. The article that Kate posted addresses everything you would need to know about your original question. Keeping your muscles warm and doing some light stretching will also help you keep the same (if not improve) muscle flexibility.

  • @Grohlier; I work in a relatively cold environment; could that explain why my biceps' size seem to fluctuate? Feb 27, 2014 at 22:58

There is a pretty logical explanation... Forgive me if I'm repeating anything anybody else has said. Inflammation occurs in the muscles during or after a workout, no matter what level of intensity. If you think about it, inflammation at varying levels always occur in muscles in use, naturally the less intense, the less inflammation, but the overall concept is that if the blood carries nutrients to the muscles, and inflammation is caused by the dilation of blood vessels in the affected area, then by applying heat, the blood vessels remain dilated and in turn transfer more nutrients at a faster rate (with that being said various factors have to be taken into account, such as respiration rate, which of course slows down during sleep along with other bodily processes) and can therefore in turn be a good method of gaining more muscle at a faster rate... Or so the theory should go, you won't know until a test is run... a small piece of what appears to be sound logic, perhaps...

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